Traffic marking system

ABSTRACT

A traffic marking system is provided wherein a material is applied in a heated condition to a roadway, the heat being developed by a novel system of agitation. The invention permits a plurality of layers of material to be applied in a single pass. The invention also provides for imbedding reflective beads in the material.

United States Patent 1 1 Ammon 1 June 28, I974 TRAFFIC MARKING SYSTEM [75] Inventor: Harry C. Ammon, Sacramento,

Calif.

[73] Assignee: State of California Department of Public Works Division of Highways 22 Filed: Dec. 20, 1972 21 App1.No.:316,757

[52] US. Cl 239/135, 239/150, 122/26, 239/172 [51] Int. Cl. BOSb 1/24, B05b 1/28, F22b 3/06 [58] Field of Search 239/130, 135, 150, 172; 122/26; 165/109 R, 109 T [56] References Cited UNlTED STATES PATENTS 11/1912 Wales 122/26 UX 10/1913 Collier 122/26 UX 11/1938 Pass 239/135 X 7/1961 French 122/26 7/1962 Cartwright 239/135 X 3,057,273 10/1962 Wilson 239/150 X 3,554,449 1/1971 Currie 239/135 FOREIGN PATENTS OR APPLICATIONS 668,905 8/1963 Canada 122/26 766,669 9/1967 Canada 239/35 371,529 3/1923 Germany 1.22/26 392,812 5/1933 Great Britain 239/135 Primary Examiner-Robert S. Ward, Jr. Attorney, Agent, or Firm-Robert G. Slick; Carl Hoppe [57] ABSTRACT A traffic marking system is provided wherein a mate rial is applied in a heated condition to a roadway, the heat being developed by a novel system of agitation. The invention permits a plurality of layers of material to be applied in a single pass. The invention also provides for imbedding reflective beads in the material.

9 Claims, 10 Drawing Figures PATENTEDmza I974 Q 3.820.718 sum 3 or 4 PIE-- .5

72 z l s: 76

/ IIJY 4 an ll 1/1 I il 78 TRAFFIC MARKING SYSTEM SUMMARY OF THE INVENTION In the past, highway striping processes have utilized marking materials which are applied at ambient temperatures and which require a considerable drying time, often on the order of to minutes. While the material is drying it has been necessary to protect the newly applied line by barriers or other means to keep traffic off of the line. This is not only a time consuming operation but it involves a substantial amount of labor to place and remove the barriers.

It has been proposed to remedy this by applying a marking material at an elevated temperature so that it dries almost instantly. However, such systems have not been fully successful since they ordinarily involve some form of gasoline fired heater which heats a heat transfer oil which is then circulated through a series of heat exchangers to transfer the heat to the material. This requires a considerable amount of start-up time and also the volume of material which must be heated at one time is so large that on completion of the operation there is a larger volume of hot material left on hand. Further, it requires a considerable amount of time to raise or lower the temperature of the material to the required temperature. Since the material is applied at a high pressure and the heating system involves burning gasoline, an extensive control system must be employed to insure safety to the operators and traveling public.

A further deficiency in the prior art processes of applying hot material is that only a single layer is applied. The material must be applied in a very thin layer since otherwise it would skin over, trapping a large amount of undried material under a top film. Thus, in some operations in the past, the material has been applied in such a thin layer that it rapidly wears out.

In accordance with the present invention, a system of applying highway marking material at elevated temperatures is provided wherein the material is heated imme' diately prior to application by mechanical working of the paint. The equipment is relatively simple compared with the heating systems employed in the past and the volume of hot material which was handled at one time is very small compared with the prior art processes. By the use of this system the problems of tire, slow startup time and overshoot at shut-down are avoided.

The device of the present invention makes it entirely feasible to apply a number of layers in quick succession. According to the invention, reflective beads can also be automatically applied with the material. In the illustrated embodiment of the invention, five layers are applied in quick succession, namely, a first material layer, a second material layer, a third layer of reflective beads, a fourth layer of material and finally a fifth layer of reflective beads. This, of course, is only illustrative of one embodiment of the invention and the reflective beads might be omitted and more or fewer layers of material might be applied.

Since the thin layer of material dries or cools almost instantly, the second and subsequent layers of material can be applied immediately over the first so that a relatively thick film of material can be built up without any problem of the material skinning over and leaving wet material under a top film.

The invention also provides a novel spray gun or nozzle means holding arm arrangement which can be mounted on an ordinary truck and which can be lowered or raised at will.

Because of the efficient system provided by the present invention, it is entirely practical to lay traffic stripes at a relatively high rate of speed, e.g. 20 miles per hour, and to not provide any barriers since one can drive over the material almost immediately without causing it to offset. I

The device of the present invention also provides a sequencing system so that the material can be applied intermittently to provide a broken line. The device of the present invention also permits one to mount more than one series of tandem spray guns on a common arm and to provide them with different colors.

The crux of the present invention resides in the method of generating the heat in situ and the precise control system which is employed to control the energy being absorbed by the material, including the ability to provide any level of heat between ambient temperature and about 400 degrees F.

Various other features and advantages of the invention will be brought out in the balance of the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a truck having a mark applying device embodying the present invention mounted thereon.

FIG. 2 is a perspective view of the truck of FIG. 1 showing it in operation applying a stripe.

FIG. 3 is an enlarged perspective view showing a typical highway stripe which might be laid in accordance with the present invention.

FIG. 4 is a diagrammatic view showing a material applying system embodying the present invention.

FIG. 5 is a front view of a material applying arm embodying the present invention.

, FIG. 6 is an enlarged section on the line 66 of FIG. 5.

FIG. 7 is a section on the line 7-7 of FIG. 6.

FIG. 8 is a top view of a stripe applying assembly wherein ll3 guns are employed for material and beads.

FIG. 9 is an enlarged sectional view on the line 9-9 of FIG. 1.

FIG. 10 is a section on the line 10-10 of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings by reference characters, there is shown in FIG. 1 a truck generally designated 11 having a retractable gun or nozzle system generally designated 13 mounted between the tandem rear wheels of the vehicle. Mounted on the truck are the various major pieces of equipment necessary for carrying out the invention, namely, a pressurized receptacle 15 for reflective heads, a tank 17 for material, a transfer pump 19 for pumping material out of the tank to an energy converter 21 to a high pressure pump 23 for delivering the material to the nozzle means or spray guns 13. Also, a control and logic device 25 is provided as well as an engine 27 with hydraulic pumps mounted thereon for driving the energy converter and the high pressure pump as well as for supplying compressed air for the operation of valves and for pressurizing the container for reflective beads.

In FIG. 2 the vehicle 11 is shown applying a broken traffic stripe 29 and in this particular instance the composite traffic stripe is composed of five layers, namely, first and second material layers 31 and 33, a first layer of reflective beads 35, a third material layer 37 and a final layer of reflective beads 39. ()bviously this is merely an example for illustrative purposes of the type of stripe which the system of the present invention is capable of laying.

With this brief description of the overall equipment, the specific components will now be described in detail.

Tank consists merely of a pressure vessel which is supplied with compressed air through line 41 and which is provided with a pressure regulating valve 43. A line 45 runs from the bottom of this tank to the gun system 13, later described in detail.

The material tank 17 is provided with a motor driven agitator 46 to keep solids in suspension and a line 48 leads from the bottom of the tank to the inlet of gear pump 19. The outlet 50 of the gear pump which leads to the energy converter unit 21. In the energy converter unit (later described in detail), the material is heated through mechanical working or agitation and passed through line 52 to the high pressure pump 23. The high pressure pump 23 is driven from the power unit 27 and in the embodiment illustrated is a double acting piston pump wherein the pressure of the material is raised to a suitable spraying pressure for airless guns which can be on the order of several hundred psi. The high pressure material is passed through the manifold line 54 to the gun system 13 and any material not dispensed through the guns is recirculated through line 56 back to the energy converter 21. Line 56 is provided with an orifice 58 which reduces the pressure to about the pressure provided by gear pump 19 which can be on the order of 25 to 50 psi. It will thus be seen that there is no large heated reservoir of material and that the small quantity of paint in circulation is almost instantly heated as it passes through the energy converter 21. Thus, the start-up time is very short and the amount of hot material left in the system at the end of the run is quite small.

A temperature sensor 61) is mounted on the energy converter 21 and is connected to the control and logic device 25. This in turn is connected to a servo which controls a variable volume pump 62 which is driven by the power unit 27 and which in turn drives the hydraulic motor 64. Thus, motor 64 is driven at an appropriate speed to hold a constant, desired temperature of the material. Since the volume of the material is quite small and is being rapidly circulated, there is little temperature drop throughout the line and the temperature of the material delivered to the gun system 13 is substantially that of the temperature of the material leaving the converter 21.

The gun unit which has been generally designated 13 is shown in detail in FIGS. 5 through 8. The unit is mounted on an arm 66 which is pivoted at point 68 on the body of the vehicle. A preferred position for the spraying head is between tandem rear wheels of a truck as is shown in FIG. 1. Extension 67 is mounted on arm 66 by bolts 69 in slotted flange 71 to permit precise positioning above the ground. Arm 66 can be raised and lowered by means of a hydraulic cylinder 70 as is shown in solid lines in FIG. 5 to a lower or operative position and in dot-dash lines in the raised or retracted positions. Extension 67 supports a plurality of spray guns which are mounted on a subframe 72 in a sliding relationship so that they can be moved horizontally to a desired point and held in a desired location by means of a set screw 741. In the embodiment illustrated there are three material guns and two dispensers for reflective beads. These are standard units and are therefore not described in detail. Each is controlled by means of air pressure in line 76 which is attached to a solenoid valve 78 leading to a source of compressed air, not shown. Heads 8t), 82 and 84 are airless material guns while heads 86 and 88 are for dispensing glass beads. The material spray guns 80, 32 and 8% each have a plenum chamber as at 81, and these chambers are connected to the inlet line 54 from the output of the high pressure material pump, previously described. The material passes successively through the various guns, as is best seen in FIG. 7 and any material which is not discharged through the guns is recycled through line 56 as previously described. The capacity of the pump is such that even if the guns are open, a substantial portion of the material will be recirculated, thus preventing any possibility of build-up in the lines. Similarly, the bead dispensers 86 and 88 are connected to the line 415 previously described. Although all five heads are shown connected to a solenoid valve 78, under some conditions it may be desirable to provide separate controls for the various guns. For instance, if laying an interrupted stripe at a low rate of speed it might be desirable for the guns to come on successively rather than simultaneously. Further, although pneumatic control of the guns is shown, electrical control can also be employed.

In FIGS. 5, 6 and 7 only a single row of guns is shown but the guns can be mounted in side-by-side arrangement as well as tandem to give multiple stripes. In FIG. 8 there are three rows of guns designated 90, 92 and 94 which are mounted in side-by-side relationships. In rows and 94 five guns are employed as was previously described, while the center unit has only three material guns and no reflective bead guns. The guns are shown applying a typical mission which comprises two outer stripes 90A and 94A of yellow material with reflective beads with a center stripe 92A of black material.

A typical energy converter which is suitable for use in the present invention is shown in detail in FIGS. 9 and 10. The converter, generally designated 21 has inlet 50, outlet 52 and a circular casing 96 with a series of director vanes )8 arranged around the periphery of the casing. A rotor or slinger 100 mounted on shaft 102 has a plurality of mating vanes 104 as well as holes 105 extending from one side of the rotor to the other. As the rotor turns part of the material that is injected through pipe 50 by pump 49 fills the converter cavity and also passes through holes 105 to fill the cavities on both sides of slinger assembly. The centrifugal motion thus imparted by rotor 104 to the material is thus the energy source of the material. The director vanes 98 cause the material to travel outward at a velocity approaching tip speed of rotor vane 98. As the material departs the tip of vanes 98 it is stopped by casing 96 which causes material to convert the energy of linear motion to heat, thus raising the temperature of the material.

The power unit 27 consists merely of a diesel engine which drives one or more pumps, the most important of which is, of course, the variable volume pump 62 which produces the heating of the material.

Many changes can be made in the exact structure shown without departing from the spirit of this invention. Other rotary energy converters can be used and various arrangements can be made for controlling the amount of energy which is dissipated as heat within the material. For instance, electric drive might be substituted for the hydraulic drive shown. Various means can also be employed for accelerating the material and for raising the pressure of the material for spraying, Specific traffic patterns have been shown but these are for purposes of illustration only and can be varied according to the mission to be accomplished.

Only one device has been shown for storing, heating and spraying material. Obviously if more than one color is to be dispensed, this equipment will be duplicated for each color.

I claim:

1. A machine for applying marking lines to a road surface and the like, comprising: a tank containing a marking material which becomes fluidized upon the application of heat thereto and which quickly dries and solidifies after it is heated and then cooled; heater means for heating and fluidizing said marking material, said heater means including a casing with an inlet and an outlet, a rotary vane means in the casing to subject material in the casing to extreme agitation and thus heat the material by conversion of mechanical energy to thermal energy; means connected with the vane means to rotate the vane means; conduit means connected to the tank and to the heater inlet to convey ma terial to be heated to the heater; high pressure pump means connected to the heater outlet; marking material applying nozzle means adjacent said pump means; conduit means connected to the pump means and to the nozzle means so that the heated material is pumped at high pressure to the nozzle means for application of the heated material to a road surface and the like; and return conduit means connected with the nozzle means and with the heater means for return to the heater means of heated material not applied through the nozzle means, only the fluid in the heater means, pump means, nozzle means and conduit means being heated, thus resulting in a substantial reduction in start up time and substantially increasing the efficiency and safety of the machine.

2. A machine as in claim 1, wherein said nozzle means comprise spray guns, and a plurality of spray LII guns are supported on a support arm, said spray guns connected in tandem with respect to one another to apply multiple layers of said marking material.

3. A machine in claim 2, wherein said machine includes means for depositing reflective beads on said marking material applied to a surface, said means includinga container of said reflective beads, conduit means connected with said container and with at least one of said spray guns. and means to cause said beads to flow through said conduit means and said at least one spray gun.

t. A machine as in claim 3, wherein there are five spray guns, said high pressure pump means connected with three of said spray guns and said container of beads connected with two of said spray guns, said spray guns arranged so that a first layer of marking material is applied to the surface and a second layer of marking material is applied thereover, a first layer of beads is applied over said second layer of marking material, a third layer of marking material is applied over said first layer of beads, and a second layer of heads is applied over said third layer of marking material.

5. A machine as in claim 1, wherein fixed vanes are in said casing to direct the marking material moved by said rotary vane means outwardly at a speed approximating the tip speed of the rotary vane means.

6. A machine as in claim 1, wherein a heat sensor is secured on said heater means to sense the temperature of the heated marking material, a servo system connected with said heat sensor and with said vane rotating means to regulate the speed of rotation of said vane means dependent upon the temperature of the heated marking material and thus maintain the temperature of the heated marking material substantially constant.

7. A machine as in claim 2, wherein each of said spray guns includes a plenum chamber, and a conduit connected serially with the plenum chambers of the plurality of spray guns to circulate the heated marking material to and through the plenum chambers for appli cation of a part of the marking material to a surface to be marked and return to the heater means of any mark ing material not applied.

8. A machine as in claim 2, wherein said support arm includes a pivotally mounted portion, said spray guns carried by said pivotally mounted portion and movable with said pivotally mounted portion to a lowered, operative position and a raised, inoperative position.

9. A machine as in claim 1, wherein is included a ve' hicle, said machine carried by said vehicle. 

1. A machine for applying marking lines to a road surface and the like, comprising: a tank containing a marking material which becomes fluidized upon the application of heat thereto and which quickly dries and solidifies after it is heated and then cooled; heater means for heating and fluidizing said marking material, said heater means including a casing with an inlet and an outlet, a rotary vane means in thE casing to subject material in the casing to extreme agitation and thus heat the material by conversion of mechanical energy to thermal energy; means connected with the vane means to rotate the vane means; conduit means connected to the tank and to the heater inlet to convey material to be heated to the heater; high pressure pump means connected to the heater outlet; marking material applying nozzle means adjacent said pump means; conduit means connected to the pump means and to the nozzle means so that the heated material is pumped at high pressure to the nozzle means for application of the heated material to a road surface and the like; and return conduit means connected with the nozzle means and with the heater means for return to the heater means of heated material not applied through the nozzle means, only the fluid in the heater means, pump means, nozzle means and conduit means being heated, thus resulting in a substantial reduction in start up time and substantially increasing the efficiency and safety of the machine.
 2. A machine as in claim 1, wherein said nozzle means comprise spray guns, and a plurality of spray guns are supported on a support arm, said spray guns connected in tandem with respect to one another to apply multiple layers of said marking material.
 3. A machine as in claim 2, wherein said machine includes means for depositing reflective beads on said marking material applied to a surface, said means including a container of said reflective beads, conduit means connected with said container and with at least one of said spray guns, and means to cause said beads to flow through said conduit means and said at least one spray gun.
 4. A machine as in claim 3, wherein there are five spray guns, said high pressure pump means connected with three of said spray guns and said container of beads connected with two of said spray guns, said spray guns arranged so that a first layer of marking material is applied to the surface and a second layer of marking material is applied thereover, a first layer of beads is applied over said second layer of marking material, a third layer of marking material is applied over said first layer of beads, and a second layer of beads is applied over said third layer of marking material.
 5. A machine as in claim 1, wherein fixed vanes are in said casing to direct the marking material moved by said rotary vane means outwardly at a speed approximating the tip speed of the rotary vane means.
 6. A machine as in claim 1, wherein a heat sensor is secured on said heater means to sense the temperature of the heated marking material, a servo system connected with said heat sensor and with said vane rotating means to regulate the speed of rotation of said vane means dependent upon the temperature of the heated marking material and thus maintain the temperature of the heated marking material substantially constant.
 7. A machine as in claim 2, wherein each of said spray guns includes a plenum chamber, and a conduit connected serially with the plenum chambers of the plurality of spray guns to circulate the heated marking material to and through the plenum chambers for application of a part of the marking material to a surface to be marked and return to the heater means of any marking material not applied.
 8. A machine as in claim 2, wherein said support arm includes a pivotally mounted portion, said spray guns carried by said pivotally mounted portion and movable with said pivotally mounted portion to a lowered, operative position and a raised, inoperative position.
 9. A machine as in claim 1, wherein is included a vehicle, said machine carried by said vehicle. 